Swab for tapered casing or tubing



Oct. 31, 1950 G. G. HEBARD swAB FOR TAPEREb cAsING oa TUBING Filed Aug. 6, 1946 N ...El mw mw vm mw mm mm IN V EN TOR. G.G. HEBARD ATTORNEYS Patented Oct. 31, 1950 SWAB FOR TAPERED CASING OR TUBING Glen G. nebara, Bartlesville, okla., assigner to Phillips Petroleum Company, a corporation of Delaware Application August 6, 1946, Serial No. 688,804

This invention relates to swabs. In one speciic aspect it relates to swabs which are self adjustable to fit and operate properly in a plurality of dimensions of pipe such as the casing or tubing of a well.

In modern practice in deep wells, it is advantageous and economical to use tapered strings of casing and tapered strings of tubing, with thinner tubing or casing for the center portion of the well Aand increasing the thickness of the walls of the casing or tubing toward the top and bottom of the well. In inserting tubing and casing in a well it is suspended from the derrick in a long string thousands of feet in length and the center portion of the string need not be as strong as the upper portion, which is supporting the lower portion, or as strong as the bottom portion which must withstand the hydrostatic collapse pressure. By making the center portion lighter, the upper portion has' less to support. The only disadvantage in this system is that the inside diameter of the tubing or casing varies from small to large and back to small again as a swab travels up the well and the swab must adjust itself to the change in diameter. The tapering of the tubing is generally not uniform, but usually consists of running several hundred pipes of a certain thickness, and then running a similar number of the next thickness, and then the next thickness, etc.,

until suicient tubing or casing has been assembled.

During the life ofl a well it is often necessary to swab the same either as a. simple pumping operation, or for other purposes such as causing pressure changes on the formation to stimulate natural iiow, or simply to remove liquids or mud from the well.

While satisfactory swabs have been produced which will work with high efliciency for long periods of time in a single internal diameter size of tubing or casing, these swabs have proved ineilicient, or inoperativeI or have rapidly broken down when used with tapered casing or with tubing having a plurality of internal diameters.

One object of the present invention is to provide an improved swab.

Another object is to provide a simple and easily operated swab having a minimum number of parts which are inexpensive to build and rugged in operation.

Another object is to provide a swab which will operate in a casing or tubing having a plurality of inside diameters.'

Another object is to provide a swab which will 17 Claims. (Cl. 10S-V225) automatically adjust itself to a wide variation in internal diameters of a pipe through which it is being pulled.

Another object is to provide a swab which uses the hydrostatic head of the liquid being lifted to seal the swab to the pipe.

Numerous other objects and advantages will be apparent to those skilled in the art upon reading the accompanying specification, claims and drawings.

In the drawings- Figure l is an elevational, cross sectional view taken through the center of a swab embodying the present invention.

Figure 2 is an elevational view with parts broken away to show details of construction of at modified embodiment of the present invenion.

Figure 3 is an elevational view with parts broken away of a third modified embodiment of the present invention.

In Figure l, a. swab generally designated as 4 is provided with a cylindrical body 5 having an extension 6 of reduced diameter. Body 5 is provided with a bail comprising arms 1 and openings 8. Bail kl is provided with attachment means 9 by which it may be attached to the usual sinker weight (not shown) and preferably rope or cable (not shown). However, swab 4 can be operated on the end of a string of tubing (not shown), if desired, but of course operation on a cable, or wire line of some sort, is preferred.

Body 5 has a iluid outlet II controlled by check valve I2. Check valve I2 allows uid to pass out of body 5 but does not permit fluid to enter body 5. Portion 6 of body 5 is provided with openings I3.

Slidable in body 5 is a piston member Il which may be provided with piston rings or other packing, such as I5, if desired. Piston I4 has areduced extension IB and a passage I'l is provided therethrough. Extension I6 extends down into portion B and may be packed thereto by cup Packing or other packing I8 secured in place by nut I9. A further extension of piston I 4 is provided by pipe 2| which could be made integral with I6, but preferably is secured thereto by suitable fastening means 22. Pipe 2| extends below the lower end of 6 and the lower end of portion 6 may be provided with a stufng box 23. Obviously close ilts could be substituted for packing at I5, I8 and 23 without invention, but such close iits are not preferred because of increased expenses resulting therefrom. Stumng box 23 may be adjusted by bolt 24.-

Passage of fluid through bore |1 is controlled by gravity check val@ 25 which may be retained in place by a suitable cage or other retaining means 28A. Access to the space inside of is provided by passage 25 in piston |4 and passage 26 is normally closed by hand op; erated shut-olf valve 21. Access to the space inside i is provided by passage '28 and vpassage 28 is controlled by hand operated shut-o valve 28. v

'A swab packer 3| consisting preferably of rubber portion 3| and metallic ends 32 and 33 securely holding the rubber 3i in place is placed around the outside of portion 8 and may be held in place by suitable retaining means 34 attached to 5 by suitable attaching means 35. While in some cases asimple cylindrical interior is sumcient it has been found preferable in such packers as 3| to corrugate the interior by horizontal corrugations 36 and it is advantageous to provide re-entrant self sealing lips- 31 on -the packer 3| at the top and bottom of the space 38 between parts 6 and 3|.

The lower end of passage i1 opens into the well bore at 38. Passage 28 leads to the well bore through valve 28.

In Figure 2, a swab generally designated as 4i is shown consisting of a center cylindrical member 42 which is provided with an enlarged base 43 which maybe integral but is preferably secured thereto at 44. 'I'he upper portion of 42 is secured to a bail 45 having arms 48 and openings 41. Bail 45 is provided with suitable securing means 48 for securing it to suitable operating means such as a sinker and rods, tubing or cables (not shown), a sinker and cable being preferred.A

Preferably secured in the upper portion of 42 is a seat 49 0n which is a gravity check valve 5| controlling ow through the opening 52 on seat 43 leading through space 53 inside of member 42. 'Ihe bail 45 acts as a cage to prevent the loss of ball 5| which is too large to pass throughopenings 41 but cannot close the same to uid flow.

Mounted on the exterior of the base 43 is a swab packer 54 secured thereto 4by such means as the annular dove tail ange 55. The upper end of packer 54 is provided with an upperly and outwardly directed lip 56 and the interior of the upper portion of the packer 54 may be lined with a suitable friction reducing and packing bushing 51 secured by suitable means 58 which may be similar to member 55.

Slidably mounted in bushing 51 (or if bushing is not present, in the top of packer 54) is an annulariypiston 59. Piston 58 may have a sealing :llt with the exterior of part 42 and the interior of part 51, which sealing nt may be produced by annular U-shaped packing rings 8| and 82 respectively. Mounted or resting on the top of piston 59 is an upwardly and outwardly directed cup packer 83. While cup packer 83 may be eliminated in some instances it is regarded as preferable because it insures the proper movement of piston 58 and in addition has some swab action. As is customary with such cup packings 53, a backing or reinforcing lip 54 may be provided on the top of piston 58, if desired, to back up packing 83 and obviate it turning inside out.

While the inside of packer 54 may cylindrical or of other shape it has been fcil( preferable to corrugate the inner side of suc A ackers with horizontal corrugations such as 35.

- packer 54 is provided by means of conduit 81, and

'lik

conduit $1 is controlled by manually operated shut-oil.' valve 58. When open, conduit 81 leads to the well bore 58.

lInvligure 3 a swab generally designated as 1I consists of a center cylindrical member 12 which may be provided at its upper end with parts 45, 46, 41, 48, 49 and 5| the same as inFigure 2. Cylindrical member 12 has an annular or top shoulder or flange 18 thereon and an enlarged based portion 14.`

A swab packer is mounted around member 12,:and disengagement therefrom is preferably prevented by collar member 16 secured to 12 by suitable fastening means 11.

While packer 15`could directly engage bore member 14 and member 12 it is preferable'to provide metallic friction reducing sealing means 13 .and 18 which may be secured to packer 15 in the same manner as part 51 in Figure 2 was secured to packer I54. 'Ihe packing effect between 18 and 14 and between 19 and 12 may be argumented by annular U-shaped packing rings 8| and 82. Packer 15 is preferably provided with suitable horizontal corrugations 33 similarly to corrugations 65 of Figure 2.

Space 84 between packer` 15 and member 12 communicates with the well bore at 85 by means of conduit 85 controlled by manually operated `shut-off valve 81.

Operation to the position shown, valve 21-being open to allow free movement of the piston. By holding the swab 4 in an inverted position and pumping piston |4 up and down any air in space 38 may be removed through lower openings i3 (at that' time they are the uppermost openings i3). When space 38 and the space between 6 and 2| is full of liquid, valve 29 is closed and then valve 21 I is closed.

Swab 4 is placed in the well and a suitable sinker weight is attached .to 9 and then a cable is attached to the sinker weight and the swab is lowered into the well. Going down the well some of the well fluid passes up around the outside of packer 3| and body 5 while other well rluid passes into 38 and up through passage I1 moving valve 25 oil' its seat and passing through openings 8.

When the bottom of the well is reached, or the swab reaches the place where it is desired to commence swabbing, the movement of the swab is reversed. As the swab travels upwardly liquid, or other fluid, above the swab passes down through the openings 8 and seats ball 25 on its seat closing passage I1. 'I'here being an upward pull on 8 from the cable and a downward push on the piston I4 from the liquid above the swab,

, piston i4 moves downward relative 4to 5 comprespand swab rubber 4 to` conform to the casing or tubing diameter is a multiple of the pressure exerted on the top of piston |4 by virtue of the smaller area between 8 and 2| as compared to the area of I4. As a result of this pressure muitiplication it is possible to obtain the necessary expanding pressure to give sumcient fiexibilty and expansion to accommodate the full range of casing or tubing sizes used in any one well.

Pulling on 9 moves the swab upwardly, Athe swab carrying and supporting all the liquid above it, and packer 3| accommodating itself to the size of the tubing or casing with which it is in contact. Upon entering the smaller internal diameter pipe packer 3| is compressed and liquid is forced back through holes I3 into the space between 5 and 2| forcing piston I4 to move up a sufficient distance. If the internal diameter of the pipe increases, a reverse action will take place automatically accommodating swab 4 to the pipe in which it is operating.

I'he operation of Figure 2 is as follows:

Space 66 is filled with liquid through pipe 61 until the piston 59 is in the position shown. Thel filling preferably takes place in an inverted position so that any air may come out of pipe 61.

\ packer, a hydraulic fluid substantially filling said When filled to the position shown, valve 58 is space, and a movable piston slidably disposed relative to said supporting member and having an upper piston head of greater area than its lower piston head, said upper head being disposed to receive the head of well liquid above said upper head and said lower head being disposed to apply said head of said well liquid from said upper head to an area of said hydraulic fluid in said space in said hollow packer which is smaller than the area of said upper head whereby the head of said well liquid above said upper head forces said packer into contact with the pipe in which the swab is operating at a pressure greater than said head of said well liquid.

2. A swab comprising in combination a supporting body, a hollow fiexible packer mounted passes up outside of packer 4| and through space 53 to lift ball 5i and passes out through space 41.

On the return trip liquid above cup 53 expands the same and liquid above lip 56 tends to expand the same into contact with the tubing, or casing, in which the swab 4 is operating.

Ball 5l is forced to its seat. Further lifting of 48 results in downward movement of piston 59 which reduces the spaces available for liquid 66, infiates packer 54 into contact with the pipe in which it is being operated.

Packer 54 automatically accommodates itsel at the different internal diameters of the pipe, ex-

panding in the larger and contacting in. the smaller pipe with resulting downward or upward movement relative to the piston 59. Extra flexibility and expansion of 54 is accomplished by multiplying the expanding pressure through differential piston and cup area.

The operation of Figure 3 is as follows:

Space 84 is filled in the same manner as space 65 was filled in Figure 2.

On the trip down the well same as Figure 2,

On the trip back up the well the top of packer 15 picks up the load of liquid above it, ball 5| seats, and the packer moves downwardly. As piston 14 is larger in diameter than piston 'I2 the liquid in 84 forces the packer 15 out into contact with the pipe the swab is in. Upon reaching a restricte/ pipe, the packer moves upward on 12 and vi H versa for a larger pipe.

.The principle of operation embodied in all three modifications shown in Figures 1 to 3 is that a large area, such as the top of I4, is depressed by the head of liquid above the swab causing a smaller area, such as the bottom of I6, to force liquid into the packer under a pressure superior to the head of liquid above the swab.

Numerous conventional changes in size, shape or arrangement of parts may obviously be made without departing from the spirit and substance of the present invention as defined in the claims.

It is recognized that if care is not used and judgment exercised in the rate 0f pulling these swabs or the amount of fluid lifted i each trip the pulling line may be overloade may break and a fishing job may result. To safeguard 4the operation is the on said body, said packer being mounted and disposed to provide a space inside said packer, a hydraulic fiuid substantially filling said space, a first piston of larger cross sectional area slidably disposed relative to said supporting body and adapted to receive on its face the weight of well liquid above said piston, a second piston of smaller cross sectional area slidably disposed within said hollow flexible packer having its head in contact with the hydraulic fluid filling said packer and being adapted to receive from said first piston the full force of the weight of well liquid above said swab and to transmit said force to said hydraulic fluid in said flexible hollow packer whereby the pressure on said hydraulic fluid is greater than the pressure exerted on the head of said first piston by said well liquid.

3. A swab comprising in combination a cylinder having a large upper end and a reduced lower end, a flexible packer mounted around said lower end, a piston having a large head fitting said upper end and a small head fitting said lower end, a space in said reduced lower end below said small head for a hydraulic fluid substantially filling said space, a conduit through said piston, a

gravity check valve controlling flow through said conduit, said large upper end of said cylinder being provided with a passage connecting the interior of said upper end to the outside, a biased 4check valve controlling flow through said passage, said biased check valve being biased to prevent flow from theoutside to the interior of said large upper end, a conduit between said reduced lower end and the space between said lower end and said packer, a conduit through said large head and a valve controlling the same. a conduit affording communication between the lower end and the atmosphere and a valve controlling the same, and means to attach said cylinder to an operating member.

4. A swab comprising in combination a cylinder having a large upper end and a reduced lower end, a flexible packer mounted around said lower end, a piston having a large head fitting said upper end and a small vhead fitting said lower end, a space in said reduced lower end below said small head for a hydraulic fluid substantially lling said space, a conduit through said piston, a

gravity cheek valve controlling now through said conduit, a conduit between said reduced lower end and the space between said lower end and said packer, aconduit through said large head and a valve controlling the same, andmeans to attach said cylinder toV an operating member.

5. A swab comprising in combination a cylin` der having a large upper end and a reduced lower end, a nexible packer mounted around said lower end, a piston having a large head tting said upper end and a small head fitting said lower end, said large upper end of said cylinder being provided with a passage connecting the interior of said upper end to the outside, a biased check valve controlling tlow through said passage, said biased check valve being biased to prevent flow from the outside to the interior of said large upper end, a space in said reduced lower end below said small head for a hydraulic uid substantially lling said space, a conduit between said reduced lower end and the space between said lower end and said packer, a conduit aording communication between the lower end and the atmosphere and a valve controlling the same, and

means to attach said cylinder to an operating member.

6. A swab comprising in combination a cylin- .der having a large upper end and a reduced lower end, a ilexible packer mounted around said lower end, a piston having a large head iitting said upper end and a `small head iitting said lower end, a space in said reduced lower endl below' said small head for a hydraulic fluid substantially fllling said space, a conduit through said piston, a gravity check valve controlling iio'w through 'said conduit, a conduit between'said reduced lower end and the space between said lower end and said packer, a conduit affording communication between the lower end and the atmosphere and a valve controlling the same, and means to attach said cylinder to an operating member.

7. A swab comprising in combination a cylinder having a large upper end and a reduced lower end, a flexible packer mounted around said lower end, a piston having a large head iitting said upper end and a small head iitting said lower end, said large upper end of said cylinder being provided with a passage connecting the interior of said upper end to the outside, a biased check valve controlling ilow through said passage, said biased check valve being biased to prevent ilow from the outside to the interior of said large upper end, a space in said reduced lower end below said small head for a hydraulic iluid substantially iilling said space, a conduit between said reduced lower end and the space between said lower end and said packer, a conduit through said large head and a valve controlling the same, `and means y to attach said cylinder to an operating member.

8. A swab comprising in combination a cylinder having a large upper end and a reduced lower end, a flexible packer mounted around said lower end, a piston having a large head fitting said upper end and a. small head fitting said lower end,

' a space in said reduced lower end below said small head for a hydraulic fluid substantially filling said space, a conduit between said reduced lower end and the space between said lower end Aand said packer, and means to attach said cylinder to an operating member.

9. A swab comprising in combination a central supporting member having a conduit therethrough and a gravity check valve closing said conduit, anupstanding exible cylindrical packer ,IUDPOrted at its lower end by, and surrounding said supporting member, a piston having a larger head above said. packer and a smaller head inside` said packer slidably disposed around said supporting member .and inside said packer to form a closed space in said packer for a hydraulic iluid substantially filling said closed space, conduit means to give access to said space, valve means controlling said conduit means, and means to attach said supporting member to an operatingmember.

l0. A swab comprising in combination a central supporting member, an upstanding ilexible cylindrical packer supported at its lower end by, and surrounding said supporting member, a plston having a larger head above said packer and a smaller head inside said packer slidably disposed around said supporting member and inside said packer to form a closed space in said packer for a hydraulic iluid substantially iilllng said closed space, and means to attach said supporting member to an operating member.

l1. A swab comprising in combination a central supporting member having a conduit therethrough and a gravity check valve closing said conduit, an upstanding ilexible cylindrical packer supported at its lower end by, and surrounding said supporting member, a piston slidably disposed around said supporting member and'inside said packer to form a closed space in said packer for a hydraulic iluid substantially lling said closed space, and means to attach said supporting member to an operating member.

12. A swab comprising in combination a central supporting member, an upstanding ilexlble cylindrical packer supported at its lower end by, and surrounding said supporting member, a piston slidably disposed around said supporting member and inside said packer to form a closed space in said packer for a hydraulic fluid substantially i'llling said closed space, conduit means to give access to said space, valve means controlling said conduit means, and means to attach said supporting member to an operating member.

13. A swab comprising in combination a central supporting member, an upstanding ilexible cylindrical packer supported at its lower end by, and surroundingsald supporting member, a piston slidably disposed around said supporting member and inside said packer to form a closed space in said packer for a hydraulic fluid substantially lling said closed space, and means to attach said supporting member to an operating member.

14. A swab comprising in combination a central supporting member having an upper small diameter and a lower larger diameter, said member having a conduit therethrough and a gravity check valve closing said conduit, a flexible cylindrical packer having an upper portion fitting said small upper diameter of said supporting member and a lower portion tting said lower larger diameter of said supporting member, an annular linternal cavity formed in said packer between said upper and lower portion for a hydraulic iluid substantially iilling said internal cavity, conduit means to-give access to said cavity, valve means controlling said conduit means, and means to attach said supporting member4 to an operating member.

l5. A swab comprising in combination a central supporting member having an upper small diameter and a lowe\larger diameter, a flexible cylindrical packer having an upper portion tting said small upper diameter of said supporting member4 and a lower portion fitting said lower larger diameter of said supporting member, anannular interval cavity formed in said packer between.

said upper and lower portion for a hydraulic iluid substantially lling said internal cavity, conduit means to give access to said cavity, valve means controlling said conduit means, and means to attach said supporting member to an operating member.

16. A swab comprising in combination a central supporting member having an upper small diameter and a lower larger diameter, said member having a conduit therethrough and a gravity check valve closing said conduit, a exible cylindrical packer having an upper portion tting said small upper diameter of said supporting member and a lower portion fitting said lower .larger diameter of said supporting member, an annular internal cavity formed in said packer between said upper and lower portion for a hydraulic iiuid substantially illling said internal cavity, and means to attach said supporting member to an operating member.

17. A swab comprising in combination a cen- 20 Number trai supporting member having an upper small diameter and a lower larger diameter, a ilexible cylindrical packer having an upper portion fitting said small upper diameter of said supporting member and a. lower portion fitting said lower larger diameter of said supporting member, an annular internal cavity formed in said packer between said upper and lower portion for a hydraulic fluid substantially filling said internal cavity, and means to attach said supporting member to an operating member.

GLEN G. HEBARD.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Name Date Leidecker Feb. 2, 1926 Thomas Mar. 22, 1932 Wilson Feb. 14, 1939 Humason Feb. 25, 1941 

